Halimeda:

Morphology: erect and forming a massive, fibrous holdfast; partially or substantially calcified, branched with flexible jointed segments. Branches are usually dichotomous.

Halimeda tuna

Species is similar to the two species mentioned after this; however, segments are large, flat and discoid; Species 5-10 cm high, branching in a single plane. Common on soft bottoms in sandy bays, on rocks and old coral; seldom in large quantities. Found throughout the year, but more frequently in spring.